Prior to consuming or processing fruits and vegetables a thorough washing is required to remove dust, pesticides, and biological contamination from the surface of the product. Bacteria that is not removed or destroyed may not only cause spoilage of the fruit or vegetable, but may also cause serious illness. Dangerous pathogens, such as Salmonella, E. coli, and Listeria, occur commonly in nature and under the right circumstances can make there way through the commercial food chain to the consumer.
Attempting to clean the fruit or vegetable by removing the products peel has been shown to be unsuccessful in eliminating the problem. Peeling knives can transmit contaminants from the surface of the skin to cells that become exposed when the peel is removed. Blanching and pasteurization processes used in the freezing, canning, and dehydrating industries do kill pathogens and thus minimize the food safety risk. However, these processes include thermal processing, which degrades texture, flavor, and nutritional value. As a result blanching and pasteurization processes fail as a suitable cleaning method when natural tasting, high quality fruits and vegetables are desired.
Often, fruits and vegetables are submerged in a cleaning solution in order to kill pathogens and remove dirt and other contaminants. Unfortunately, fruit and vegetables that float, such as apples, peaches, plums, and peppers, create difficulties during washing. The area most subject to contamination is the depression on top of the fruit where the stem connects because the fruit is oriented upwards when hanging on the tree forming a pocket that collects dust and harbors bacteria. Certain fruit, such as apples, tend to float stem up, making the depression on the top of the fruit difficult to clean without special and costly attention.
Traditionally, brush washers and flume washers are commonly used to clean produce yet both fail to adequately clean the dirtiest area of the fruit. Brush washers typically employ rotating bristles to scrub the surface of the fruit or vegetable. Unfortunately, the rotating bristles fail to penetrate into recesses, thus leaving the dirtiest area of the fruit or vegetable, such as the depression on an apple, untouched.
While flume washers attempt to immerse the fruit or vegetables, many floating fruits fail to be cleaned adequately. Bins of produce may be dumped into flumes and hydraulically conveyed to other processing equipment, such as sorters or peelers. Immersion of the product, typically occurring only when the fruit and vegetable is initially dumped into the flume, often serves as the only washing step prior to processing. Many fruits, such as apples, and vegetables float with their stem oriented upwards, out of the water. As a result of the limited and random contact with water, the flume washers also fail to adequately clean the dirtiest part of the fruit or vegetable.
To enhance the cleaning process, water sprays have been added to brush and/or flume washers. However, speed of travel and orientation of the product in a flume washer is not well controlled, making positive contact by the sprays on all surfaces uncertain and sporadic. Brush washers traditionally control product movement with greater accuracy, but the brushes themselves are inherently a sanitation issue. Dirt, foreign material, and organic matter often becomes packed or wedged between the brush bristles, providing a natural growth medium for bacteria. This cohesive mixture hardens with time, is difficult to remove, and forms a barrier to chemical treatment, eventually resulting in expensive maintenance or replacement.
Antimicrobial agents, such as chlorine, ozone, chorine dioxide, peroxyacetic acid, and peroxide are added to wash water to reduce bacteria population on the product and to control bacterial growth in the wash water and on equipment surfaces. To achieve maximum effectiveness and elimination of pathogens, product must be exposed to the sanitizing solution for a given amount of time. A direct correlation exists between bacteria reduction and exposure time. Unfortunately, however, there is no precise means to control exposure time or to ensure uniform coverage of all product surfaces with brush and flume washers, making it difficult to ensure that minimum exposure times have been met. Therefore, a thorough and reliable washing process is a critical part of ensuring fresh-cut ready-to-eat fruits and vegetables are safe for the consumer.
Therefore, there is a need for a method and apparatus for washing fruits and vegetables that float with precise control of exposure time to the cleaning solution, and with precise product movement to ensure complete solution exposure to all product surfaces.